What are 4 initial/embryonic divisions of the central nervous system? What do they become?

What further specialization takes place in the CNS in embryonic development?

the prosencephalon splits into the telencephalon (cerebrum/hemispheres) and the diencephalon (thalamus - sensory relay station and hypothalamus); the rhombencephalon divides into the metencephalon (pons & cerebellum) and the myelencephalon (medulla)

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What are the two main divisions of the peripheral nervous system? What do they do?

What are the divisions of the autonomic PNS?What do they do?

sympathetic nervous system (fight or flight); parasympathetic nervous system (return to rest; homeostasis)

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Where is the central nervous system and how is it protected? How is this different than the PNS?

it is housed w/in bony structure (skull/vertebral col) and covered with protective tissue/membranes (meninges divided into three layers, pia mater, arachnoid mater, dura mater) The PNS does not have this bony protection

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What is meant by interconnectivity?

there is a functional organization: L & R hemis communicate via corpus collosum, association areas (mainly in the parietal lobe) different modalities come 2gether (ex. writing uses motor, lang, and visuals); basic reflexes (patella reflex, hot stove) - don't require brain, just travel to spinal cord, complex reflexes (lifting a light box, like its a heavy box), may req brain involvement, but both use the brain to store in memory, sensory and motor areas must work together

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How does the CNS control everything?

it integrates all incoming and outgoing info, creates responses (volitional and reflexive- spinal cord); no two parts of the PNS communicate w/o the CNS

What is meant by laterality?

even though the two cerebral hemispheres are almost symmetric anatomically, there is hemispheric specialization: left controls language and analytic skills; right controls emotion, prosody, big picture/gestalt, pragmaticscontralateral sensorimotor control

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What are the three sensory methods of organization of the cerebrum?

somatotopic - sensory/motor organization based on region of the body (somatosensory cortex is just post central sulcus; primary motor cortex is just pre central sulcus);tonotopic organization of the auditory cortex/Heschel's gyrus (org based on sound)retinotopic organization of the visual cortex; certain locations of objects trigger certain parts of the occipital lobe;

What are subcortical structures?

cell bodies that are deep to the cortical structures

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What is a fasciculus/tract?

groups of axons (CNS: tract; PNS: fasciculus); in the PNS are more bundled and are nerves, but as they spread the

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What is a commissure?

band of connecting fibers; connect the right and the left hemispheres; corpus callosum is the largest in the brain; anterior commissure is for olfactory connection; posterior commissure is for visual connection

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What is the major sulcus which divides the anterior and posterior halves of the brain?

the central sulcus (sulcus of Rolando); more difficult to see

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What is the major sulcus which divides the left and right hemispheres?

sagittal sulcus (longitudinal fissure)

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What is the line which makes the little arm in the brain (separating the temporal lobe and the frontal and parietal)? The thumb of the boxing glove brain

What are the landmarks of the the frontal lobe?

the pre-central gyrus BA 4 - where the motor homunculus is;the supplementary motor area BA6 and premotor area BA8 imp for movement planning

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What are the two sections of the parietal lobe? What are they divided by?

the superior and inferior; the intraparietal sulcus

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What are three other important areas of the parietal lobe? What is they important?

the angular gyrus (at the posterior end of the sylvian fissure) & the supramarginal gyrus (superior & anterior to the angular) - important for reading and writing (lang comprehension; post-central gyrus - sensory strip of the body

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What is the anterior most boundary of the temporal lobe?

the temporal pole

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What is the purpose of the superior temporal gyrus? What are the areas called?

What structures are on the inferior surface of the temporal lobe?

the uncus (very important to the limbic system, very medial)the parahippocampal gyrus (just superficial to the hippocampus and medial to the inferior temporal gyrus); fusiform gyrus (extension of the parahippocampus; functions in recognizing things)

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Where is the hippocampus? What does it look like? What does it do?

deep/medial in the temporal lobe; squiggly; seahorse shaped; transforms short term into long term memory

Where is the hypothalamus? What is the function?

Where is the thalamus? What is it made of? What does it do?

inf to the septum pellucidum; third ventricles divides the two thalami; consists of multiple nuclei; sensory relay to cortex; also SOME speech/language functions; sense of smell does NOT stop here, but everything else does;

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What shape is the caudate nucleus?

c-shaped

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Where is the putamen?

lateral to the caudate

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Where is the globis pallidus?

deep/internal to the putamen

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What is the subthalamic nucleus?

a small lens-shaped nucleus; part of the basal ganglia system;

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What does substantia nigra mean? What does it do?

black substance, darker than the surrounding tissue; where dopamine made

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Where are the anterior and posterior commissure?

axon tracts that connect the two hemispheres at the front and back end of the corpus callosum

What gray matter/ exists in the brain stem?

the longitudinal fiber tracts

What is the corticobulbar tract?

motor tract that start in the cortex ends in the brain stem

What is the corticospinal tract?

motor tract that start in the cortex ends in the spinal cord

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What is a pyramidal tract?

one set of tract that traverses the brain stem

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What is the reticular formation?

part of the brain stem/ neurons that connect the thalamus and spinal cord; regulates inhibit, facilitates, modifies all cortical function; integrated w/ the autonomic nervous system (fight or flight and return to homeostasis) (influences signal up or down)

What is the reticular formation? What does it do?

What is the corpora quadrigemina? Where is it?

four bumps on the dorsal/posterior of the midbrain; the superior colliculus (regulates visual reflexes, integrates head & eye movements, reflexive eye mvts); inferior colliculus (hearing - point on the pathway to the temporal lobe

What is the function of hte cerebellum? What are its extensions?

What are the features of the cerebellum? 4

the gyri are called folia (b/c they are tiny, lots more surface area than the cerebrum); the vermis is the (midline structure), it has two hemispheres, flocculonodular lobe (inferior extension)

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What is the spinal cord?

a bi-directional pathway for axons; it houses reflex arcs;

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How long is the spinal cord? How wide?

16-18 inches long; 1 cm diameter

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How many pairs of spinal nerves are there? What is their break down?

31 pairs; 8 cervical; 12 thoracic; 5 lumbar; 5 sacral; 1 coccygeal

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What is the h-shaped/butterfly shaped structure in the spinal cord made of? What is the surrounding structure made of?

cell bodies; axons (reversed from the brain)

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What is the lower tip of the spinal cord? What is below it?

the conus medullaris;the filum terminale (fiber extending down to connect to the coccyx) and the cauda equina (tail of nerves exiting to innervate lower extremities)

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What are the two "horns" of the spinal nerve cells?

the dorsal horns (sensory exiting); ventral horn (mostorentering)

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Where do the fibers exit/enter the spinal cord?

the intervertebral foramina

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The dorsal and ventral fibers combine and become ___

spinal nerves

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What are the fiber tracts of the white matter of the spinal cord called?

funiculi/fasciculi; can be labeled for where they connect, or what they do

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How does they spinal cord change in size as it descends?

there are fewer nerves as you reach the bottom, there is more gray matter near the limbs, more white matter rostrally, w/ sensory, more and more is added as the cord ascends, the gray matter increases in percentage at the sacral region because all of the motor neurons for the lower limbs must exit there.

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What is the ventricular system?

the set of the cavities and canals, which are filled with cerebrospinal fluid (CSF); the ventricles are all connected

the axon hillock; may split into collateral branches;

What are the tiny packets of chemicals found at the end of an axon?

What is the cytoskeleton?

structural proteins that give the cell its shape (composed of microtubules neurofilaments, and microfilaments that run the length of the axon: they continue down axons and create "roadways" for transporting proteins and organelles

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What are tau proteins?

important proteins for microtubules

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Most of the neurons are covered with ___. What does this do?

myelin; it's a fatty substance that increases the speed of signals travelling down the axons

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What are nodes of Ranvier?

portions of the axon that are not covered by myelin, jumping points

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What is a nerve fiber?

a myelinated axon

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What are nerves?

bundles of nerve fibers

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What is the myelin sheet?

fatty tissue created by either schwann cells or oligodendrocytes (it speeds up neural conduction)

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How are Schwann cells different than oligodendrocytes?

each Schwann cell creates one packet of myelin; but oligodendrocytes create multiple myelin packets (also Schwann is in PNS, oligodendrocytes are in CNS)

How much faster is myelinated axons than unmyelinated?

10 m/s to 120 m/s

What is myelogensis?

The point of communication between two neurons or between the neuron and the muscle is the ____

synapse

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Is there physical contact at a synapse?

no.

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What are the components of the synapse? 3

the axon terminal; the synaptic cleft and the receptors/receptor sites

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What are the steps in the sending of a message?

dendrites receive a chemical message and send it to the soma/cell body; the soma gest the msg from the dendrites, sends electrical msg down the axon; axon transports electrical msg to axon terminal; axon terminal sends chemical signal through the synapse to the next neuron (usually through a dendrite)

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What are the two types of signals a cell body can send?

excitatory ("go" signal) or inhibitory ("stop" signal); both can be sent, whichever has more is going to win (be passed on)

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What are tau proteins?

important proteins for microtubules

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Most of the neurons are covered with ___. What does this do?

myelin; it's a fatty substance that increases the speed of signals travelling down the axons

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What are nodes of Ranvier?

portions of the axon that are not covered by myelin, jumping points

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What is a nerve fiber?

a myelinated axon

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What are nerves?

bundles of nerve fibers

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What is the myelin sheet?

fatty tissue created by either schwann cells or oligodendrocytes (it speeds up neural conduction)

How much faster is myelinated axons than unmyelinated?

10 m/s to 120 m/s

What is myelogensis?

The point of communication between two neurons or between the neuron and the muscle is the ____

synapse

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Is there physical contact at a synapse?

no.

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What are the components of the synapse? 3

the axon terminal; the synaptic cleft and the receptors/receptor sites

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What are the steps in the sending of a message?

dendrites receive a chemical message and send it to the soma/cell body; the soma gest the msg from the dendrites, sends electrical msg down the axon; axon transports electrical msg to axon terminal; axon terminal sends chemical signal through the synapse to the next neuron (usually through a dendrite)

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What are the two types of signals a cell body can send?

excitatory ("go" signal) or inhibitory ("stop" signal); both can be sent, whichever has more is going to win (be passed on)

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What are the two types of signals that can be sent?

1. electrical signal (w/in a neuron, has to do with Na and K moving in and out of the cell from soma to axon terminal) 2. chemical signal (neuro transmitter function transferring a signal from one neuron to another or muscle cell)

How do synapses work in the PNS?

they attach at the neuromuscular junction

Motor neurons extend out from the ____ of the spinal cord.

ventral body

What are the presynaptic neurons steps (3)?

1 msg sent down axon to terminal, 2 neurotransmitters released from vesicles in axon terminal, 3 neurotransmitters spill into synaptic gap

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What are the postsynaptic neuron steps (3)?

1 neurotransmitter binds to receptors on dendrite, 2 responds to presence of neurotransmitter, 3 sends message to next neuron

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How do electrical signal work?

called action potentials or nerve impulses, they are sent w/in a neuron, ion channels & ion pumps make this happen (Na, K, and Ca)

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How do chemical signals work?

at the synapses, neurotransmitters (dopamine, norepeniphrene)

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What is the resting state of a neuron characterized by?

it is not conducting a signal/impuls, and the membrane potential is polarized (it is negative inside, positive outside the cell membrane); lots of sodium outside, some potassium, chloride ions, and negatively charged proteins inside the cell. The inside of the cell is -70 mV relative to the outside (cell is polarized)

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What are the ions involved in electrical signal transmission?

Sodium (Na+), Potassium (K+), Chloride (Cl-), Calcium (Ca++)

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What are the two membrane potential gradients in the neuron?

membrane potential (concentration gradient: ion concentration gradiate means that there is more one kind of ion outside than inside; electrical gradient - the difference in the charge (-70mV);

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What are ion channels?

openings for free ion movement (sodium will move inside and potassium will move outside the cell to balance the ion concentration)

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What are ion pumps?

energy-powered pumps to move ions in/out (used to recreate the gradient found in the resting state - pump potassium in and sodium out)

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What are leak channels?

allow ions to just flow in and out (allow potassium to leave cell, allow chloride in, they do not affect the electrical charge/gradient)

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How do the membrane potential and the sodium-potassium pump work?

the membrane potential is the fact the Na and Cl are high outside the cell and K is greater inside the cell and the sodium-potassium pump restores this gradient using energy

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What is neuron excitability?

its potential for creating an impulse to send to the next neuron or cell

What is exocytosis?

What happens when the neurotransmitters enter the synaptic cleft?

it binds to the receptors, if it is excitatory, it will open the sodium channels and become depolarized, creating an excitatory post-synaptic potential (EPSP); if it is inhibitory, it creates hyperpolarization or inhibitory post-synaptic potential (IPSP)

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What are EPSP neurotransmitters?

ACh, Glutamate, Dopamine, and Seratonin

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What is an IPSP neurotransmitter?

GABA, also barbituates and "downers"

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What happens after the neurotransmitter finishes binding? 2 options

it releases and re-enters the synaptic cleft and some go through reuptake enter the axon terminal and can be rebound for the next and others can be consumed by enzymes.

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What are the rules governing an action potential? 3

1 initiated when depolarization reaches the threshold 2 it is all or nothing 3 it is the same magnitude each time

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What is the absolute refractory period?

a period after an action potential, when sodium channels are inactivated/locked w/ strong depolarization, this prevents new AP until repolarization occurs

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What is a relative refractory period?

the hyperpolarized state, -80 mV; needs a bigger stimulus to fire (need more work, more EPSPs to fire)

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What is summation?

the addition of charges, which determines if the EPSPs or IPSPs are greater

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What is spatial summation?

the location of the greatest charge is localized and as a result, causes an AP

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What is temporal summation?

if one neuron fires repeatedly, can over come another neuron's firing (IPSP or EPSP)

What are the small molecule neurotransmiters? 6

What is acetylcholine?

common in the PNS, primary Ntx found at the neuromuscular junction

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What is acetycholine esterase?

an enzyme that breaks down ACh at synapse and allows repittive neve impulses; allows muscle repolarization

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How does Myasthenia Gravis affect ACh function?

an autoimmune disease that causes antibodies to interfere with ACh receptors at neuromusclar junction, affects the muscles over time (speech will be come slurred as the pt speaks); swallow will get weaker and weaker over time

For what can drugs that increase the effectiveness of GABA be used?

Where is Glutamate found?

in CNS, synaptic vesicles

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What does Glutamate do? What's the deal?!

it is the primary excitatory Ntx in the CNS, most neurons will have receptors to Glutamate so that they can responds to it wherever it's released. it is toxic to the external cell membrane if it escapes (this is called excitotoxicity- where it escapes and there is too much excitation in a system, damage between) - one of the reason for neuropathologies in nearby areas to trauma.

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What types of neuronal circuits are there? 4

divergent circuit - signal from 1 neuron to may neurons (amplifies impulse)convergent circuits - many inputs (from 1 or many neurons) into 1 post-synaptic neuron, focusing impulses;lateral inhibition - sending an EPSP to a target cell and IPSPs to neighboring cells; amplifies 1 by shutting down the othersreverberating circuit - self-propagating system

How quickly does Wallerian degeneration happen? When does Myelin degeneration take place?

What happens to the soma after injury? 5

1 the organelles begin to swell, 2 Nissl substance degenerates, 3 chromatolysis (9-10 days after injury- shrinking of the nucleus) degeneration of the cell body btw axon hillock & nucleus; 4 pyknosis (condensation of chromatin in the nucleus of a cell undergoing necrosis), 5 nucleus moves away from the center of the soma

it begins 3-4 days post injury; can be surgically cleaned/re-attached;

What cells assist in PNS regeneration and how? 3 steps

How widespread is re-growth re-connection in the CNS?

minimal

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What limits regrowth in the CNS?

oligodendrocytes actions and inflammation

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What is multiple sclerosis? (meaning and process)

sclerosis means scarring, and it is an autoimmune disease attacking the myelin; glial cells proliferate and form plaques/scars which disrupts function and slows nerve conduction over time; the immediate affect is slowing of function

symptoms = pt reportedsigns = doctor observed

What are the later signs and symptoms of MS?

What is the relapsing/remitting pattern of MS?

some people will have periods where things seem to get better, and then things seem to get worse: oligodendrocytes decide to help create new myelin for a while, then stop and relapse can cause axon death (permanent damage)

What are the Pt characteristics of MS?

How widespread is re-growth re-connection in the CNS?

minimal

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What limits regrowth in the CNS?

oligodendrocytes actions and inflammation

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What is multiple sclerosis? (meaning and process)

sclerosis means scarring, and it is an autoimmune disease attacking the myelin; glial cells proliferate and form plaques/scars which disrupts function and slows nerve conduction over time; the immediate affect is slowing of function

symptoms = pt reportedsigns = doctor observed

What are the later signs and symptoms of MS?

What is the relapsing/remitting pattern of MS?

some people will have periods where things seem to get better, and then things seem to get worse: oligodendrocytes decide to help create new myelin for a while, then stop and relapse can cause axon death (permanent damage)

What are pt's characteristics of ALS?

What is the progression of ALS?

slowly progressive, but can progress rapidly; symptoms include muscle twitching, cramping, stiffness, muscle weakness in arms/legs, gradually spreads to both head/neck and body; cognition affected, but later in the disease

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Who are famous people with ALS?

Lou Gherig, Stephen Hawking

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What are the components of the diencephalon?

thalamus, hypothalamus, epithalamus, subthalamus, and the optic tract (anterior extension of the diencephalon)

____ has connections to the mamillary body to the cingulate gyrus and plays a role in emotion and visceral functions (digestive, respiratory systems).

anterior nucleus of the thalamus

centromedian and intralaminar nuclei of the thalamus

The ___ connects to/from the cortex diffusely and plays a role in attention and wakefulness. It covers the thalamus.

reticular nucleus of the thalamus

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What are 2 important parts of the epithalamus?

the habenular nucleus and the pineal gland

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______ is connected to the hypothalamus, limbic system, orbitofrontal cortex, reticular formation that plays a role in emotion, drive, smell and memory/smell systems. It is named after a horse's reins.

habenular nucleus

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____ is an endocrine system gland which secretes melatonin, and influences gonadal systems, sleep/wake cycles and Seasonal Active Depression.

pineal gland

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_____ is connected with the motor system, the basal ganglia, globus pallidus, and superior colliculus. Anatomically related to the thalamus.

word finding difficulties and difficulties naming objects

What do lesions of the thalamus cause? 5

Stimulation of parts of the thalamuscan help with ____ recall, ___ retrieval, and can influence ____ behaviors.

verbal recall, lexical retrieval, and stuttering behaviors

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_____ is disfunction which is marked by altered threshold for sensation (touch, pain, temperature), with contralateral input, Pain is poorly localized, can have an increased pain threshold, but increased pain response above threshold OR decreased pain threshold.